I'm just learning about Bitcoin and if I understand its conception properly, mining bitcoins means validation of transactions by computing a hash which should satisfy some preset condition. In other words, mining == servicing network and getting money for it.

If Satoshi was the first user, how did he earn his bitcoins if there were no transactions?

I understand, that in the very beginning some geeks were involved in the network, so maybe 5 or 10 persons' (first testers) transactions and their validation (mining) generated a lot of bitcoins, because of the low difficulty and high reward. But how did the very first coins get rewarded?

So, since transactions are no requirement, blocks are limited differently: It happens through the difficulty. Miners create block candidates continuously, and then check each whether it fulfils the difficulty requirement. Whenever they find a block that surpasses the required difficulty, they have successfully mined a block. As the difficulty resets regularly to adapt to changes in the hashrate of the mining network, the blocks work out to be discovered approximately every ten minutes.

In the very beginning of Bitcoin, mining difficulty was very low as there were few people running their home computers to mine Bitcoin. Satoshi Nakamoto was the first one to run a computer for mining, and thus was able to mine a large portion of the early blocks.

Still confusing as ever. I understood the question but not the answer. Could this be explained ever simpler?
– invnibleJan 17 '16 at 8:14

@invnible: The asker thought that blocks need to confirm transactions in order to be created. However, empty blocks are allowed. Only the transaction that creates the new money is necessary, but it is created by the miner himself.
– Murch♦Jan 17 '16 at 10:03

In simple terms: mining a block = finding a hash that matches with the previous block's hash + optionally a bunch of unconfirmed transactions.

A block doesn't need to include any transactions. And if there are unconfirmed transactions, a block may include all, some, or none of them.

If there are, it's in the miner's best interest to include them all. He earns the mining fees on top of the block reward, and it doesn't make the hash computation of the new block any more difficult. So deliberately not including pending transactions = leaving free money on the table. But mining can still occur even if there are no transactions at all.

Besides, even if it was required to include transactions, Satoshi could of course have sent dummy transactions between addresss of his own (and collecting his own transaction fees).